The present invention generally relates to an anastomosis of living tissue and, more particularly, it relates to a surgical instrument particularly adapted for use in the installation of an assembly of interlocking coupling members to achieve compression anastomosis of tubular structures. The instrument, developed to facilitate placement of the coupling assembly in a patient and to enhance in the removal of the instrument after placement, includes a novel cutting element which incorporates a rotary motion as the cutter advances through tissue and the coupling assembly. Additionally, the instrument might include a unique locking feature to improve operational safety, a unique coupling member aligning feature to enhance both in positioning of the coupling members and in applying compressive force to the members, and a unique flexible portion to accommodate a variety of surgical conditions.
A compression anastomosis coupling assembly is typically used when a segment of colon, or like tubular organ, is to be resected. After a section of the colon is removed, leaving opposed, proximal and distal, free ends, coaxially oriented coupling members are introduced, aligned and brought into locking engagement. The coupled members capture and compress the free ends of the colon together to effect an anastomosis by holding tissue in compression until healing occurs. Blood supply to the captured tissue is restricted. Necrosis takes place in the area of the colon captured within the assembly without causing excessive inflammation and trauma. Thereafter, the coupled assembly detaches from the anastomotic site and is expelled spontaneously through the rectum. After assembly expulsion, the colon provides an open passageway at the anastomotic site substantially as that which existed before resectioning.
Disclosure of a known type of surgical instrument used to install an assembly for circular anastomosis of hollow organs can be found in U.S. Pat. No. 4,681,108. This device advanced the then known art field by introducing a circular mechanical anastomotic gun suitable for performing circular anastomosis in hollow organs using a compressive device. Previously, in the majority of cases, a mechanical gun had been used in systems incorporating a number of metallic staples which were driven into tissue edges to achieve the anastomosis. Specifically, the device disclosed in the aforementioned patent includes three coaxial tubular elements, means for carrying and means for positioning members of a coupling assembly, a circular cutting blade, and a driving means for first advancing the coupling members into engagement and then advancing the circular blade for cutting. The new surgical instrument herein disclosed further advances the art field by introducing a cutter which rotates as its advances. The rotational movement of the cutter has the advantages of reducing the cutting force necessary to cut through both captured excess organ tissue and a coupling member of the assembly to provide an open passageway for material passage therethrough. The existing patented instrument includes a threaded knob which is rotated for positioning the outer coupling element and for exerting a compressive force between the outer and intermediate coupling elements prior to full locking assembly of the coupling elements. The present device enhances coupling member positioning by providing a sliding-approximation system for easier and quicker operation. Also, the present device might feature an automatic locking system for securing one of the coupling members in a variety of positions relative to the other coupling members as a further refinement of the sliding approximation system. Furthermore, the sliding approximation system is designed and configured to provide an increased mechanical advantage thus reducing the necessary force applied by the user to achieve compression between assembly coupling members. An additional feature of the new instrument which is an improvement over known devices relates to an improved safety locking system which provides for alternately locking the instrument aligning and driving features. Specifically, the locking feature allows for either aligning or driving at a given instant but not simultaneously, namely, when the aligning feature is operational the driving feature is inoperative and, conversely, when the driving feature is operational the aligning feature is inoperative. Also, the new instrument might be either disposable or reusable. Furthermore, the instrument might include an anatomically curved segment for ease in introducing the device into a patient. Lastly, an improvement not known in the art is that the instrument might be sufficiently flexible to accommodate a variety of anatomical orientations and operating conditions.
The primary objective of the present invention is to further advance the art field by providing a surgical instrument which is used to establish compression anastomosis in tubular organs and which is an improvement over existing devices. Accordingly, herein disclosed is a surgical instrument which is especially designed and configured for greater ease in installation of a compression anastomosis coupling assembly and which incorporates a rotary cutting device. Furthermore, the instrument might incorporate unique locking, aligning and orienting features for enhanced device safety and operation.